Constructing novel electroluminescent device with high

Subscriber access provided by CARLETON UNIVERSITY

Applications of Polymer, Composite, and Coating Materials

Constructing novel electroluminescent device with high-temperature and high-humidity resistance based on flexible transparent wood film Tao Zhang, Pei Yang, Minzhi Chen, Kai Yang, Yizhong Cao, Xinghui Li, Miao Tang, Weimin Chen, and Xiaoyan Zhou ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.9b09331 • Publication Date (Web): 06 Sep 2019 Downloaded from pubs.acs.org on September 6, 2019

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Applied Materials & Interfaces

Constructing novel electroluminescent device with high-temperature and highhumidity resistance based on flexible transparent wood film Tao Zhang,†,‡ Pei Yang,†,‡ Minzhi Chen,†,‡ Kai Yang,§ Yizhong Cao,†,‡ Xinghui Li,†,‡ Miao Tang,†,‡ Weimin Chen,,†,‡ Xiaoyan Zhou,†,‡ †College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, China ‡Fast-growing Tree & Agro-fibre Materials Engineering Center, Nanjing 210037, China §College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China E-mail:

[email protected], [email protected]

Keywords: low coefficient of thermal expansion, flexible electroluminescent devices, silver nanowire, transparent electrode, veneer



Corresponding author. E-mail address: [email protected].  Corresponding author. E-mail address: [email protected].

ACS Paragon Plus Environment

ACS Applied Materials & Interfaces 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Abstract Plastic-based electroluminescent devices generally suffer from thermal expansion owing to the high coefficient of thermal expansion (CTE) of the plastic substrate, which reduces the service lifetime of the electroluminescent device. In this study, we employed a delignified veneer synergistically reinforced with epoxy resin as a low-cost substrate for Alternating Current Electroluminescent (ACEL) devices. In brief, the natural interconnected porous structure of wood had a good anti-deformation capacity to restrict the volume expansion of the epoxy resin under thermal conditions. Furthermore, the impregnation of epoxy resin dramatically improved the optical transmittance of delignified veneer. Considering its low CTE and anti-deformation capability, the intrinsically high-temperature and high-humidity resistance device based on transparent sliced veneer (TSV) was constructed. Remarkably, the TSV-ACEL device exhibited an excellent stability and maintained good luminescence performance even at a high temperature (100 °C, 30 min; as a reference, the PET-based ACEL device has stopped operating), completely submerged in water (30 min) or at a hightemperature and high humidity conditions (90 °C, relative humidity: > 90%, 30 min). These results pave the way for the realization of flexible and high-temperature resistance ACEL devices.

Introduction Alternating current electroluminescent (ACEL) devices can be employed in various applications including displays, lightings, and signal expressions owing to their simple structures, uniform luminescence performances, and adjustable luminescence wavelengths.1-3


Page 2 of 33

Page 3 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


As the commonly used material for ACEL devices, glasses have advantageous on high transmittance and low coefficient of thermal expansion (CTE).4 However, considering the high brittleness, particularly in some large displays, glass will emit broken debris upon a sudden impact. This drawback limits its application in flexible ACEL devices. Plastic films (e.g. polyethylene terephthalate (PET) and polyimide (PI)5, 6), as promising substitutes for glass, with distinct advantages of flexibility and safety under a strong impact, are widely used for the fabrication of ACEL devices. For the plastic-based ACEL device, the middle luminescent layer is usually attached on the substrate. The mismatch between the different functional layers is a major source of failure in ACEL devices, So the thermal expansion of the plastic film significantly affects the interface compatibility between the plastic substrate and luminescent layer, thus reducing the service lifetime of the electronic product. The ACEL devices, supported by conductive substrates, typically require low CTE (smaller than 20 × 10−6 K−1) to relieve thermal stresses upon heating.7 Nevertheless, the CTE of PET and PI can reach 86.37 × 10−6 and 48.54 × 10−6 K–1, respectively.8, 9 Such high CTE value cannot meet the requirements for the substrates of the ACEL devices.10, 11 Extensive studies have been carried out to reduce the CTE and improve the thermal stability by designing composites. For example, fillers with low CTE and excellent thermal conductivities (e.g., carbon fiber reinforcement,12, 13 chromium carbide coating,14 glass fiber enhancement,15 and organophilic montmorillonite reinforcement16) have been extensively applied to effectively reduce the CTE value. But the colored fillers generally lower the transparency of the composite materials. Therefore, the demand for materials that simultaneously exhibit low CTE and outstanding transmittance has driven the continuous



studies for the fabrication of advanced flexible displays. Cellulose nanofiber functional materials have been widely used in green electronics, biological devices, energy, and other fields mainly owing to their natural degradation and abundant raw materials.17-20 In addition, the cellulose nanofiber has a similar light refractive index to those of most transparent polymers, especially epoxy resin.21-23 Furthermore, the CTE of cellulose nanofibers in the axial direction is only 0.1 × 10−6 K–1.24 These excellent properties enable the cellulose nanofibers were widely used in reinforcing polymer matrices, and provide a new platform for the preparation of composite materials with low CTE. However, the cellulose nanofiber functional materials, usually derived from wood, are fabricated through a complex homogenization process. Traditional fabrication method for cellulose nanofiber is time and energy-consuming and environmentally unfriendly.25, 26 In this study, by removing the colored lignin from birch sliced veneer, the basic structure of the wood was well preserved. Benefiting from the efficient incorporation of epoxy resin within the delignified wood structure, the chemical bonds were formed between delignified veneer (hydroxyl groups) and epoxy resin (epoxy groups), thus contributing more to the interface strength. Meanwhile, the natural interconnected porous structure of wood has a good capacity to restrict the volume expansion of the epoxy resin under thermal conditions. In comparison to the transparent PET film, the synergy between wood and epoxy resin film (denoted as transparent sliced veneer (TSV)) provided a better deformation resistance, lower CTE, and outstanding transmittance. Benefiting from these characteristics, the intrinsically high-temperature and high-humidity resistance electroluminescent device based on TSV was fabricated. We designed three illumination modes to demonstrate its applicability in ACEL


Page 4 of 33

Page 5 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


devices. The stability of the TSV-ACEL device was verified during operations at a high temperature, under water immersion or at a high -temperature and high- humidity environment. Experimental section Materials Birch sliced veneer with dimensions of 60 mm × 40 mm × 0.25 mm was obtained from Jinhu Hongda Wood Industry. Sodium chlorite (NaClO2, 80%) was purchased from Shanghai Macklin Biochemical Co., Ltd., China. Glacial acetic acid (CH3COOH, analytical reagent (AR)) and ethanol alcohol (CH3CH2OH, AR) were supplied by Nanjing Chemical Reagent Co., Ltd., China. Silver nanowires (AgNWs) with diameters of 70-200 nm and lengths of 3050 µm were purchased from Shanghai Bohan Chemical Technology Co., Ltd., China. Epoxy resin (#3601 epoxy resin (A) and #3601 (B) tetraethylenepentamine hardener with a ratio of 1:1, commercial name: Hasuncast 3016(A/B)) was supplied by Huasheng Tong Chuang Technology Co., Ltd., China. The ZnS:Cu microparticles with an average diameter of 14.79 μm were purchased from Shanghai Keyan Phosphor Technology (KPT) Company. All reagents and solvents were used as received without further purification. Lignin removal process A delignification solution was prepared as follows. First, 487.5 mL of deionized water, 12.5 g of NaClO2, and 0.48 g of CH3COOH were mixed and magnetically stirred for 10 min. The birch sliced veneer was then transferred in the lignin removal solution at 80 °C until the sample completely turned white. Delignified veneer sample was then carefully washed with



distilled water three times (each cycle lasted 10 min) to remove the residual solution. Subsequently, the extracted sample was washed with anhydrous ethanol for further rapid drying. Finally, delignified veneer was sandwiched between two glass slides and placed in an oven at 55 °C to evaporate the anhydrous ethanol. Preparation of the TSV film The preparation process of flexible epoxy resin is as follows. Using the balance to weigh 15g of #3601 A and 15g of #3601 B. Then mixed the AB glue thoroughly with magnetic stirring for 10 min. The dried delignified veneer was fully impregnated with epoxy resin under vacuum. Approximately 15 min later, the vacuum was released and the flexible epoxy resin was filled into the delignified veneer structure under atmospheric pressure. The above process was repeated three times to ensure the epoxy resin fully penetrated the wood lumen. Finally, the prepolymerized delignified veneer sample was taken out and sandwiched between polytetrafluoroethylene molds for further polymerization. Fabrication of the flexible TSV-ACEL device The TSV-ACEL device was fabricated using the TSV film as the substrate electrode. First, dielectric barrier discharge air plasma was employed to graft hydroxyl functional groups on the TSV film with a power of 120 W for 2 min. AgNWs (diluted to a concentration of 1.0 mg·mL−1 in ethanol alcohol) were then sprayed on the surface of the TSV film using a spray gun (Air flow: 20-23 L/min, Distance: 6 cm, Pressure range: 5-43 PSI, Auto stop: 3 BAR/43 PSI, Auto start: 2 BAR/29 PSI, Air tank: 0.2 L). The TSV sample was then treated for 5 min in an oven at 60 °C to remove residual ethanol alcohol solvents. We could obtain different


Page 6 of 33

Page 7 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


luminescent patterns directly by controlling the shape of the upper electrodes (e.g. mushroom and tree). A copper strip was bonded to the edges of the AgNW networks as a lead for the external circuit. ZnS:Cu microparticles mixed with epoxy resin (mass ratio of 2:1) were spun onto the TSV electrode at a spin velocity of 4000 rpm for 30 s. The average deposition volume was 0.00176 cm3 (20×20 mm area as an example). Subsequently, another AgNWs/TSV film was prepared by the same procedure and placed on the luminescent layer. The structure was laminated for 3 min at 80-100 kPa in an automatic vacuum laminator. Characterization and measurement Field-emission scanning electron microscopy (FE-SEM, JSM-7600F, JEOL, Japan, operating at an acceleration voltage of 15 kV) was used to analyze the surface and cross section of the TSV film. Fourier-transform infrared (FT-IR) spectrometry (VERTEX 80V, Bruker, USA, 4000-500 cm−1) was used to measure the component changes of the TSV film sample. Ultraviolet-visible spectrometry (Lambda 950, PE, USA) in the spectral range of 300 to 800 nm was carried out to evaluate the transmittance of the TSV film. The transparency was measured according to American Society for Testing and Materials (ASTM) D1003 (standard method for haze and luminous transmittance of transparent plastics). An Instron 5966 testing machine was used to study the mechanic properties with a crosshead speed of 5 mm min−1. The TSV film was cut to dimensions of 50 mm × 5 mm × 0.25 mm. Laser confocal microscopy (LSM 710, ZEISS, Germany) was used for imaging of the lignin autofluorescence. A thermal expansion analyzer (TMA 402 F3, NETZSCH, Germany) was used to evaluate the CTE of the TSV sample at a heating rate of 10 °C min−1 in the range of 10 to 100 °C under nitrogen flow. A thermogravimetric (Tg) analysis (Tg 209 F3, NETZSCH, Germany) was carried out at a



rate of 10 °C min−1 in the range of 10 to 800 °C under nitrogen atmosphere. The TSV film was treated by an atmospheric-pressure dielectric barrier discharge plasma. Air plasma was generated between two plane-parallel aluminum electrodes; the upper high-voltage aluminum electrode was covered with an insulating quartz glass layer. The sheet resistance of the conductive and transparent sliced veneer (CTSV) film was measured using a Keithley 2110 digital multimeter with a four-point probe. The surface functional groups of the TSV film before and after the plasma treatment were analyzed by X-ray photoelectron spectroscopy (XPS, AXIS UltraDLD, Kratos). The crystal structures of the ZnS:Cu particles were characterized through X-ray diffraction (XRD, Ultima IV, Rigaku) using Cu Kα radiation. The luminescence spectrum of the TSV-ACEL device was measured using a spectrophotometer (PhotoReasearch, PR-655, USA). A Konica Minolta CS-150 luminance and color meter was used to measure the luminance of the TSV-ACEL device. The EL intensity and bias voltage on the TSV-ACEL device can be evaluated by Seq. (1) (supporting information). Results and discussion Preparation and analysis of delignified veneer Wood have different structures owing to the different growth locations and environments, while the regularly aligned channels in the direction of wood growth are the common characteristics for all types of wood. The highly ordered interconnected pore networks formed by cells during tree growth are used for water, ion, and oxygen transport.27 According to the chemical structure, a mature cell in wood can be divided into cell walls, cell cavity, and middle lamella. The cell walls are formed mainly by three polymer compounds intertwined with each


Page 8 of 33

Page 9 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


other.28 Cellulose is present in the cell wall in the form of microfibril bundles, imparting tensile strength to the wood and functioning as a cell wall skeleton. Hemicellulose usually permeates into the cellulose skeleton. Lignin is an amorphous polymer, which tightly binds to hemicellulose and provides the wood with mechanical strength.29 An idealized schematic of the lignocellulose architecture was shown in Figure 1a. After the wood sample was treated with NaClO2, the colored lignin was removed. Surprisingly, the basic framework of wood was successfully retained, which was beneficial for the impregnation of epoxy resin and limitation of the thermal expansion of the epoxy resin. The distribution and morphological characteristics of lignin in the wood cell wall were observed in Figure 1b. FT-IR spectroscopy was performed to elucidate the removal efficiency of lignin. The peak at 3345 cm−1 corresponds to the characteristic O–H stretching vibration. The peak at 2915 cm−1 can be attributed to methyl, methylene, or methyne stretching vibration. The broad absorption band at 1739 cm−1 corresponds to the acetyl groups in hemicelluloses, while the absorption band at 1622 cm−1 is assigned to the C=O stretching vibration.30 Furthermore, the peak at 1036 cm−1 can be assigned to the C–OH stretching band.31 A partial enlarged FT-IR spectrum was shown in Figure 1c. The peaks at 1593 and 1505 cm−1 correspond to the phenyl ring stretching vibration, which was attributed to aromatic skeleton vibrations of lignin. The absorption peaks at 1461 and 1422 cm−1 correspond to the C–H deformations in lignin and carbohydrates. As illustrated in Figure 1c, the characteristic peaks at 1593, 1505, 1461, and 1422 cm−1 almost disappeared after the NaClO2 treatment, indicating that the lignin was successfully removed from the birch veneer sample.32 As lignin is a self-fluorescent material, the effect of the lignin removal can be evaluated by investigating the fluorescent intensity.33 Figure 1d shows that the fluorescence



signal of the wood samples disappeared after 2.5 h of treatment. The color changes of the birch samples during the lignin removal process were shown in Figures S1a-f (supporting information). The successful removal of lignin turned the yellowish wood into completely white after NaClO2 treatment, which can be attributed to the retention of the colorless cellulose and the removal of colored lignin. In terms of the fabrication of the substrate for ACEL devices, the preparation of delignified veneer is considerably more time-saving (2.5 h) and costeffective than the fabrication of cellulose nanofiber.

Figure 1. (a) Schematic of the aligned cellulose and hemicellulose in the birch veneer before and after lignin removal. (b) Lignin fluorescence images on radial section of original veneer along the wood growth direction. (c) FT-IR to investigate the effect of lignin removal. (d) Lignin fluorescence intensity changes of wood samples treated with NaClO2 for 0 h, 1 h and 2.5 h, respectively.


Page 10 of 33

Page 11 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Structural analysis of wood before and after impregnation with epoxy resin Figure 2a illustrates the birch sliced veneer obtained by longitudinally cutting the birch wood block. The partial enlarged view in Figure 2c shows that the well-arranged channels in the growth direction of wood ensure the full impregnation of epoxy resin. Figures 2d and 2e demonstrate the delignified veneer and TSV film, respectively. It is worth noting that the epoxy resin infiltration and delignification process cannot destroy the channels of the original veneer structures. Figures 2f and 2g show partial enlarged SEM views of delignified veneer and TSV, respectively. The cross section of the wood exhibits that the empty lumen was tightly surrounded by the cell wall. The middle lamella of the lignin-rich region was severely destroyed after the wood sample was treated by NaClO2, leading to a large gap between the wood cells during the drying process (Figure 2f). The macro-pore size distributions of the original veneer and delignified veneer was shown in Figure S2 (supporting information). As revealed by the results from mercury porosimetry, the porosity of wood changed from 55.95% (original veneer) to 61.72% (delignified veneer). The well-arranged channels in the wood growth direction were fully occupied by epoxy resin, as shown in Figure 2e and the partial enlarged view in Figure 2g.



Figure 2. (a) Birch veneer was cut along the growth direction (channels direction) of the wood. The color of the original veneer was yellowish while it turned completely white after 2.5 h of treatment with NaClO2. (b) The internal channels (along the wood growth direction) of wood sample. (c) Zoomed in SEM image to show the wood lumen. (d) and (e) are the cross-sectional images of the delignified veneer and TSV to show the porous structure changes. (f) and (g) are the locally enlarged cross-sectional SEM images to show the middle lamella structure changes. The middle lamella was a lignin-enriched area. The middle lamella of delignified wood was destroyed, resulting in a large void.


Page 12 of 33

Page 13 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Transmittance and mechanical properties of TSV film The pore structure along the wood growth direction and mismatched refractive indices between wood and air can easily cause light scattering.34 In addition, the dark color and high light absorption capacity of lignin are responsible for the non-transparent wood. Therefore, the process of removing lignin and impregnating of epoxy resin (refractive index 1.53) are the necessary for the preparation of transparent wood.35 The total transmittance of original veneer and delignified veneer were only 1.3% and 3.4% in the wavelength range of 300-800 nm (see Figure 3a). In contrast, the film exhibited a high optical transmittance when the delignified veneer was impregnated with epoxy resin. These results indicate that a highly flexible and transparent wood film was successfully prepared by embedding the delignified veneer into epoxy resin, as shown in Video S1 (supporting information). The total light transmittance of the TSV film reached as high as 85% at 800 nm. Therefore, the fabricated TSV exhibited a higher transmittance than that of the original veneer sample. Although the transmittance of TSV was slightly lower than that of cellulose nanopapers (more than 90%),36 it could be obtained by a simple process. For the original veneer, delignified veneer, and transparent PET film, the fracture strength was up to 22.15 MPa, 16.74 MPa, and 48.87 MPa respectively (see Figure 3b). Compared with TSV film (fracture strength was reach up to 62.75 MPa), the fracture strength of the pure epoxy resin was only 1.45 MPa (Figure 3c) which was much lower than that of resultant TSV composite, thus demonstrating the robust reinforcing effect of wood structure toward the epoxy resin. Therefore, the mechanical properties of TSV substrate provide a mechanical guarantee for ACEL devices.37



Figure 3. (a) The optical transmittance of original veneer, delignified veneer, and TSV composite film, respectively. Inset: The optical transmittance (500 nm-520 nm) of original veneer, delignified veneer, respectively (b) Experimental stress-strain curves for the original veneer, delignified veneer, TSV film, transparent PET film, respectively. (c) The stress-strain curves for pure epoxy resin.

Coefficient of thermal expansion and thermal stability of TSV film The thermal and dimensional stabilities are crucial for light-emitting devices as they can enable the substrate film to withstand a high-temperature deposition, so as to ensure a precise coordination of the different functional layers in the light-emitting device even under the high temperature.38 In order to evaluate the thermal expansion performance, both PET and TSV films were placed on a heating plate at 100 °C. The transparent PET exhibited a significant irreversible warpage change (Figure S3, supporting information). In contrast, the TSV film retained its original shape and thickness even after 30 min on the heating plate, evidencing its potential as an electronic devices substrate for operating at high temperature, as shown in Figures 4a, 4b, and Figure S4 (supporting information). As the natural interconnected porous structure of wood would limit the volume expansion of the epoxy resin during the heating process and improved the interfacial interaction between the ingredients. As shown in Figure 4c, the CTE value of TSV film with an epoxy resin content of approximately 64.28 wt% (Table


Page 14 of 33

Page 15 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


S1, supporting information) is much lower than that of PET film and epoxy resin film. Such high CTE valve of PET ((86.37  3.62) × 10‒6) and epoxy resin film ((76.89  3.53) × 10‒6 K‒1) cannot meet the requirements for a display device substrate operating under hightemperature conditions. Figures 4d and 4e show the Tg and derivative thermal gravimetric (DTG) curves of the TSV film, respectively. For the epoxy resin, the first stage (150 to 300 °C) involved the elimination of water formed by dehydration of secondary alcohols, formation of unsaturated structures, and branching reaction of molecular chains.8 As shown in Figure 4d, the onset decomposition temperature of the original veneer was 258 °C, which can be attributed to the pyrolysis of cellulose and hemicellulose.39 The onset temperature of the TSV film was 238 °C which was higher than that of the epoxy resin (150 °C) and lower than that of wood (258 °C). There was no mass loss of transparent wood film below 200 ℃, indicating that TSV was relatively stable at high temperature. The temperature corresponding to the maximum weight loss rate can be obtained using the DTG curve. The rapid degradation occurred within the structure of the flexible TSV film at a temperature of 361 °C (see Figure 4e). According to the CTE and Tg results, the fabricated TSV film has the potential for applications in hightemperature-resistant ACEL devices.



Figure 4. (a) When the TSV film was placed on the heating plate for 30 minutes, the shape changes were observed from the top view and the side view. (b) The shape changes of transparent PET film. (c) The CTE of TSV film. (d) Tg and (e) DTG curves of TSV film, epoxy resin and transparent PET film, respectively.

Sheet resistance and transmittance of the CTSV film A previous study has shown that if AgNWs are directly sprayed on the surface of the hydrophobic film, the adhesion of the AgNWs and substrate is usually unsatisfactory owing to the incompatible features between the substrate and conductive AgNWs (TSV is hydrophobic, while the AgNWs are hydrophilic40). Therefore, the air plasma technique was employed to enhance the surface accessibility of the TSV film through the grafting of


Page 16 of 33

Page 17 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


functional groups. A schematic of the preparation of the CTSV film was presented in Figure 5a in which AgNWs were deposited on the TSV film using a spray gun. Airbrush spray deposition has demonstrated the ability to control nanoscale anisotropic thin films with tailored networks.41 Even at the 180° bending state, the CTSV film can still light up lightemitting diodes (see Figure 5b). The pristine TSV film was hydrophobic with a water contact angle of approximately 94°. It became hydrophilic with a water contact angle of approximately 55° upon the air plasma treatment, as shown in Figure 5c. Figure 5d shows the FT-IR spectra of the untreated TSV film and air-plasma-treated film. The broad absorption band at 3382 cm−1 corresponds to the stretching vibration of hydroxyl groups, while the absorption band at 1739 cm−1 is assigned to the carbonyl groups. The absorption peaks at 1183 and 1246 cm−1 correspond to ether groups. The above peaks show the obvious signal enhancement after the air plasma treatment, implying the generation of plentiful oxygen-containing free radicals and functional groups.42 The bands at 1610 and 1510 cm−1 are attributed to the aromatic ring of resin. The absorption bands at 1450, 1385, and 2965 cm−1 correspond to the methylene groups.43 Further, XPS was carried out to accurately analyze the surface chemical changes in the elements and chemical functional groups of the untreated and air-plasma-treated TSV films. As shown in Figure 5e, the three strong peaks at binding energies of 285, 400, and 532 eV correspond to C 1s, N 1s, and O 1s, respectively. As the TSV sample was treated under air atmosphere, a characteristic peak of nitrogen was observed. Figure 5e shows that the oxygen content was increased from 13.45% to 29.34% after 2 min of air plasma treatment, indicating the successfully incorporation of oxygen on the surface of the TSV substrate. In addition, the C 1s spectrum of the TSV film can be fitted by four peaks, ascribing to four carbon-related



chemical states, as shown in Figures 5f and 5g. The dominant peak centered at 284.8 eV is attributed to C–C or C–H groups. The peak centered at 286.1 eV is attributed to C–O groups. The other two adjacent peaks centered at 287.3 and 288.9 eV correspond to C=O or O–C–O and O–C=O groups, respectively. The content of oxygen-containing functional groups (C–OH, C=O, COOH, Table S2, supporting information) on the surface of the TSV film was considerably increased after the air plasma treatment, indicating that the polarity of the TSV film was improved. This suggests that the air plasma treatment led to the decrease in contact angle, yielding a better wettability of the TSV substrate. The transmittances and fracture strengths of the CTSV are shown in Figures 5h and 5i, respectively. The aggregation of AgNWs during the spraying reduced the transmittance of the CTSV film to 80.5%. As shown in Figure 5i, the fracture strength of the CTSV is 60.57 MPa, which almost equal to that of the TSV film. Figure 5j shows the sheet resistances of AgNWs with different area densities on the TSV substrate (defined as the weight of AgNWs per unit substrate area, Seq. (2), supporting information). The area density of the AgNWs was increased from 42 to 349 mg/m2, while the corresponding sheet resistance decreased from 108 to 10 Ω sq−1.


Page 18 of 33

Page 19 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 5. (a) Graphical illustration of the fabrication process for the CTSV film. (b) The original state and bending state of the CTSV film. (c) Static water contact angle of TSV film after air plasma treatment. (d) FT-IR spectra of the of TSV film after air plasma treatment. (e) XPS spectra of survey scanning for TSV film before and after air plasma treatment. (f) High-resolution C 1s XPS spectra before air plasma treatment. (g) High-resolution C 1s XPS spectra after air plasma treatment. (h) The optical transmittance of CTSV film. (i) Stress-strain curves for the CTSV film. (j) The sheet resistance of AgNWs with 42 mg/m2, 65 mg/m2, 114 mg/m2, 195 mg/m2, 302 mg/m2, 349 mg/m2, respectively.



Fabrication of the TSV-ACEL device The TSV-ACEL device was fabricated by sandwiching an elastic ZnS:Cu/epoxy resin luminescent layer with two AgNWs/TSV electrodes, as shown in Figure 6a. We designed three modes (mushroom, square, tree) by controlling the shape of the top electrode substrate (Figure S5, supporting information). When the top and bottom conductive electrodes were connected to an alternating current, a stable electric field was formed. The intermediate luminescent layer was accelerated to a high-energy state under the electric field. The accelerated carriers caused ionization of the luminescent center to generate electron-hole pairs. The relaxation of excitons led to luminescence.44, 45 Figures 6b, 6c, and 6d show the actual luminance of the TSV-ACEL device under dark environment. The SEM image of the TSV-ACEL device was depicted in Figure 6e. The TSV-ACEL device was a standard three-layer structure having a thickness of 543 μm. Figures 6e and 6f show that the ZnS:Cu particles were uniformly dispersed in the epoxy resin layer. The morphologies of the ZnS:Cu particles with an average diameter of 14.79 μm were shown in Figures S6a and S6b (supporting information). The composition of the ZnS:Cu particles was analyzed by energy-dispersive spectroscopy (EDS), yielding an atomic ratio of Zn:Cu:S of 68.11:0.25:31.63 (Figure S6c, supporting information). The powder XRD pattern in Figure S6d confirmed that the ZnS:Cu particles had a wurtzite structure (JCPDF No. 36-1450). An FE-SEM image and corresponding EDS map of the ZnS:Cu particles were shown in Figure S7 (supporting information). The dependence of the EL layer thickness on the spin-coating velocity was shown in Figure S7b (supporting information). The photoluminescence spectrum of the ZnS:Cu particles was presented in Figure S8 (supporting information). The emission


Page 20 of 33

Page 21 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


spectrum (energy band structure of ZnS:Cu) shows that the Cu dopant levels provided an effective radiative recombination path for the excitations.46 In this study, AgNWs were directly sprayed on the surface of the TSV film and simultaneously buried by the luminescent layer. The whole conductive network was constrained, thus the structure does not shift and lose conductive capacity under bending-releasing operations.44 It is impossible to evaluate the change in the sheet resistance when the TSV was in the bent state owing to the covering of the ZnS:Cu luminescent layer. Therefore, we directly sprayed the AgNWs on the TSV film when the epoxy resin was unpolymerized and simulated the effect of the luminescent layer covering. The adhesion of the epoxy resin enabled the AgNWs to be physically attached to the TSV substrate, thereby limiting the junction damages and inter-nanowire sliding for an improved bending ability, as shown in Figure 6g. Even after 500 cycles of bending, the sheet resistance did not change, suggesting the excellent conductivity stability of the CTSV (Figure S9, supporting information). The morphological observation of the AgNWs demonstrated that their diameters were 129.5  27.5 nm (Figure 6g and Figure S10, supporting information). Owing to the coverage of the ZnS:Cu/epoxy resin layer, the contact between the AgNWs and air could be considerably avoided, thus protecting the AgNW networks from oxidation.47



Figure 6. (a) Schematic of the preparation of TSV-ACEL device. Three different illumination modes of TSV-ACEL device were designed by controlling the shape of the upper electrodes((b) Mushroom, (c) Square, (d) Tree). (e) The structures of the TSV-ACEL device (obtained from the cross section). (f) Zoomed in SEM image to show the microstructure of ZnS:Cu luminescent particles. Inset: the top view of the luminescent layer. (g) Microstructure of AgNWs.

The EL emission spectrum of the TSV-ACEL device was shown in Figure 7a. The luminescence peak at 464 nm has a full width at half maximum of 80 nm. The International Commission on Illumination (CIE) color coordinates were (0.1492, 0.2003), implying that a typical blue emission was generated by the device. The EL spectrum and CIE color coordinates of the PET-based ACEL device are shown in Figure S11 (supporting information). Figure 7b


Page 22 of 33

Page 23 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


shows the luminance of the TSV-ACEL device under different applied voltages in the range of 0 to 220 V at different frequencies. The light emission from a bias voltage of approximately 70 V provided a luminance of 0.23 cd/m2, while those at a bias voltage of 220 V were 15.73 cd/m2 at 400 Hz, 30.31 cd/m2 at 1 kHz, 48.26 cd/m2 at 2 kHz, 75.96 cd/m2 at 5 kHz, and 104.87 cd/m2 at 10 kHz. As a reference, the luminance of the PET-based ACEL device was up to 31.05 cd/m2 at a voltage of 220 V (at 1 kHz, Figure S12, supporting information). It can be observed from Figure 7c and Video S2 (supporting information) that the luminance can still reach 29.09 cd/m2 when the TSV-ACEL device was placed on a heating plate for 30 min at 100 °C, suggesting its good thermal stability. The TSV-ACEL device also exhibited a good luminescence stability upon heating at 150 °C for 30 min (Video S3, supporting information), while the TSV film turned yellow upon the heating for 30 min, as shown in Figure S13 (supporting information). The luminance decreased from 30.30 to 15.32 cd/m2, which is likely attributed to the decrease in the transmittance of the TSV film at 150 °C, thus the light emitted from the device could not be completely transmitted from the TSV substrate. Subsequently, we changed the light-emitting mode of the TSV-ACEL device to demonstrate its good luminescence stability (Video S4, supporting information). In contrast, the brightness of the ACEL device based on the transparent PET considerably decreased and the luminescence was stopped when the temperature reached 100 °C. Because ZnS:Cu luminescent particles were dispersed in epoxy resin and the luminescent layer was directly attached on the CTSV substrate, the device has good waterproof performance without additional sealing processes (Figure 7d and Video S5, supporting information). The excellent waterproof performance of ACEL could be attributed to the enhanced interface strength and improved thermal stability.



Considering the above results, we simulated an environment with a high temperature of 90 °C and a relative humidity (> 90%) in the laboratory to evaluate the tolerance of the fabricated TSV-ACEL device (Figure S14, Videos S6 and S7, supporting information). As shown in Figure 7e, the device luminance changed from 30.31 to 29.16 cd/m2 when the device was exposed to the environment for 30 min. In our experiment, as luminescent particles were directly dispersed in the flexible epoxy resin, the bonding strength can be guaranteed. The SEM image showed the good combination of the layer and the TSV substrate. The bonding shear strength of the TSV-ACEL device can reach a maximum of 2.702 MPa, as shown in Figure 7f. It is worth mentioning that the TSV-ACEL device exhibited a uniform bright light emission even under bending and twisting (Figure S15, supporting information). According to the above results, the proposed TSV substrate is very promising for the fabrication of the hightemperature and humidity-resistant flexible ACEL devices.

Figure 7. (a) Electroluminescent spectrum and position of Commission Interationale de L’Echairage (CIE) color coordinates of the TSV-ACEL device. (b) The luminance of the TSV-ACEL device under different applied voltages in the range of 0 to 220 V at different frequencies. (c) The luminance changes when the


Page 24 of 33

Page 25 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


TSV-ACEL device and PET-ACEL device were respectively placed at 100 °C and 150 °C (220V, 1 kHz). (d) Luminance changes of TSV-ACEL device when it was completely immersed in water (220V, 1 kHz). (e) Luminance changes of TSV-ACEL device under high temperature (90 °C) and relative humidity (> 90%, 30 min) conditions (220V, 1 kHz). (f) The bonding shear strength of the TSV-ACEL device.

Conclusion In summary, we fabricated a flexible TSV film simultaneously exhibited a low CTE value (3.94×10‒6 K) and high transmittance (85%). Transparent PET film showed a significant irreversible shape warpage change, while the TSV film remained its original shapes and high transmittance even after 30 min at 100 ℃. On the basic of good thermal stability and low CTE, we successfully fabricated the TSV film as the low-cost substrate for ACEL devices. By controlling the shape of the top electrode substrate, different modes including a mushroom, a square, and a tree can be fabricated accordingly. Since the ZnS:Cu/epoxy resin functional layer was attach on the TSV film, the TSV-ACEL device can still give off bright light no matter it was hollowed out, cut into half or twisted. The TSV-ACEL device exhibited waterproof properties without additional processes to seal, and had excellent high-temperature and highhumidity resistance, evidencing that the fabricated TSV film have potential applications in high-temperature resistant ACEL devices.

ASSOCIATED CONTENT Supporting Information The Supporting Information is available free of charge on the ACS Publications website.



Calculating formula of luminance and definition of AgNWs area density; characterization of the color and shape changes of TSV substrate; the schematic of different illumination modes; measurement of the morphology and photoluminescent (PL) spectrum of ZnS:Cu particles; the bending-releasing test and the particle size distribution histogram of AgNWs samples; performance analysis of PET-ACEL device; detailed description of the simulated hightemperature and high-humidity conditions. AUTHOR INFORMATION Corresponding Author E-mail: [email protected] (X.-y. Z.) E-mail: [email protected] (W.-m. C.) Author Contributions The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. Notes The authors declare no competing financial interest. Acknowledgements The authors are grateful to the National Natural Science Foundation of China (Grant No. 31870549), the Jiangsu Nature Science Foundation (BK20161524), the Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX17_839), the start-up funds for scientific research at the Nanjing Forestry University (163020126), the Advanced Analysis and Testing Center of Nanjing Forestry University.


Page 26 of 33

Page 27 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Reference (1) Cho, S. H.; Jo, S. S.; Hwang, I.; Sung, J.; Seo, J.; Jung, S. H.; Bae, I.; Choi, J. R.; Cho, H.; Lee, T.; Lee, J. K.; Lee, T. W.; Park, C. Extremely Bright Full Color Alternating Current Electroluminescence of Solution-Blended Fluorescent Polymers with Self-Assembled Block Copolymer Micelles. ACS Nano 2013, 7, 10809-10817. (2) Stauffer, F.; Tybrandt, K. Bright Stretchable Alternating Current Electroluminescent Displays Based on High Permittivity Composites. Adv. Mater. 2016, 28, 7200-7203. (3) Liang, G. J.; Hu, H. B.; Liao, L.; He, Y. B.; Ye, C. H. Highly Flexible and Bright Electroluminescent Devices Based on Ag Nanowire Electrodes and Top-Emission Structure. Adv. Electron. Mater. 2017, 3, 1600535. (4) Devan, R. S.; Patil, R. A.; Lin, J. H.; Ma, Y. R. One-Dimensional Metal-Oxide Nanostructures: Recent Developments in Synthesis, Characterization, and Applications. Adv. Funct. Mater. 2012, 22, 3326-3370. (5) Wang, J.; Liang, M. H.; Fang, Y.; Qiu, T. F.; Zhang, J.; Zhi, L. J. Rod-Coating: Towards Large-Area Fabrication of Uniform Reduced Graphene Oxide Films for Flexible Touch Screens. Adv. Mater. 2012, 24, 2874-2878. (6) Wu, H.; Kong, D. S.; Ruan, Z. C.; Hsu, P. C.; Wang, S.; Yu, Z. F.; Carney, T. J.; Hu, L. B.; Fan, S. H.; Cui, Y. A transparent electrode based on a metal nanotrough network. Nat. Nanotechnol. 2013, 8, 421-425. (7) Nogi, M.; Yano, H. Transparent nanocomposites based on cellulose produced by bacteria offer potential innovation in the electronics device industry. Adv. Mater. 2008, 20, 1849-1852. (8) Xiong, B.; Zhong, W. B.; Zhu, Q.; Liu, K.; Li, M. F.; Sun, G.; Wang, D. Highly transparent



and rollable PVA-co-PE nanofibers synergistically reinforced with epoxy film for flexible electronic devices. Nanoscale 2017, 9, 19216-19226. (9) Miyagawa, T.; Fukushima, T.; Oyama, T.; Iijima, T.; Tomoi, M.; Photosensitive Fluorinated Polyimides with Constant Based On Reaction Development a Low Dielectric Patterning. J. Polym. Sci. Pol. Chem. 2003, 41, 861-871. (10) Huang, X. Y.; Jiang, P. K.; Tanaka, T. A Review of Dielectric Polymer Composites With High Thermal Conductivity. Ieee Electr. Insul. Mag. 2011, 27, 8-16. (11) Chen, X. G.; Guo, J. D.; Zheng, B.; Li, Y. Q.; Fu, S. Y.; He, G. H. Investigation of thermal expansion of PI/SiO2 composite films by CCD imaging technique from - 120 to 200 °C. Compos. Sci. Technol. 2007, 67, 3006-3013. (12) Lalet, G.; Kurita, H.; Heintz, J. M.; Lacombe, G.; Kawasaki, A.; Silvain, J. F. Thermal expansion coefficient and thermal fatigue of discontinuous carbon fiber-reinforced copper and aluminum matrix composites without interfacial chemical bond. J. Mater. Sci. 2014, 49, 397402. (13) Godara, A.; Mezzo, L.; Luizi, F.; Warrier, A.; Lomov, S. V.; van Vuure, A. W.; Gorbatikh, L.; Moldenaers, P.; Verpoest, I. Influence of carbon nanotube reinforcement on the processing and the mechanical behaviour of carbon fiber/epoxy composites. Carbon 2009, 47, 2914-2923. (14) Tang, Y. X.; Wang, L. H.; Zhao, C. Enhancement of the thermal properties of silverdiamond composites with chromium carbide coating. Appl. Phys a-Mater. 2014, 115, 379385. (15) Zhou, J. T.; Yao, Z. J.; Chen, Y. X.; Wei, D. B.; Wu, Y. B. Thermomechanical analyses of phenolic foam reinforced with glass fiber mat. Mater. Des. 2013, 51, 131-135.


Page 28 of 33

Page 29 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(16) Jia, Q. M.; Zheng, M.; Zhu, Y. C.; Li, J. B.; Xu, C. Z. Effects of organophilic montmorillonite on hydrogen bonding, free volume and glass transition temperature of epoxy resin/polyurethane interpenetrating polymer networks. Eur. Polym. J. 2007, 43, 35-42. (17) He, M. H.; Zhang, K. L.; Chen, G. X.; Tian, J. F.; Su, B. Ionic Gel Paper with Long-Term Bendable Electrical Robustness for Use in Flexible Electroluminescent Devices. ACS Appl. Mater. Interfaces 2017, 9, 16466-16473. (18) Zhu, M. W.; Jia, C.; Wang, Y. L.; Fang, Z. Q.; Dai, J. Q.; Xu, L. S.; Huang, D. F.; Wu, J. Y.; Li, Y. F.; Song, J. W.; Yao, Y. G.; Hitz, E.; Wang, Y. B.; Hu, L. B. Isotropic Paper Directly from Anisotropic Wood: Top-Down Green Transparent Substrate Toward Biodegradable Electronics. ACS Appl. Mater. Interfaces 2018, 10, 28566-28571. (19) Okahisa, Y.; Yoshida, A.; Miyaguchi, S.; Yano, H. Optically transparent wood-cellulose nanocomposite as a base substrate for flexible organic light-emitting diode displays. Compos. Sci. Technol. 2009, 69, 1958-1961. (20) Zhang, Z.; Wang, H. Y.; Li, S. Y.; Li, L.; Li, D. G. Transparent and flexible cellulose nanoflbers/silver nanowires/acrylic resin composite electrode. Compos. Pt. A-Appl. Sci. Manuf. 2015, 76, 309-315. (21) Yano, H.; Sasaki, S.; Shams, M. I.; Abe, K.; Date, T. Wood Pulp-Based Optically Transparent Film: A Paradigm from Nanofibers to Nanostructured Fibers. Adv. Opt. Mater. 2014, 2, 231-234. (22) Zhu, M. W.; Song, J. W.; Li, T.; Gong, A.; Wang, Y. B.; Dai, J. Q.; Yao, Y. G.; Luo, W.; Henderson, D.; Hu, L. B. Highly Anisotropic, Highly Transparent Wood Composites. Adv. Mater. 2016, 28, 5181-5187.



(23) Liao, H. Q.; Wu, Y. Q.; Wu, M. Y.; Zhan, X. R.; Liu, H. Q. Aligned electrospun cellulose fibers reinforced epoxy resin composite films with high visible light transmittance. Cellulose 2012, 19, 111-119. (24) Nishino, T.; Matsuda, I.; Hirao, K. All-cellulose composite. Macromolecules 2004, 37, 7683-7687. (25) Jonoobi, M.; Oladi, R.; Davoudpour, Y.; Oksman, K.; Dufresne, A.; Hamzeh, Y.; Davoodi, R. Different preparation methods and properties of nanostructured cellulose from various natural resources and residues: a review. Cellulose 2015, 22, 935-969. (26) Moon, R. J.; Martini, A.; Nairn, J.; Simonsen, J.; Youngblood, J. Cellulose nanomaterials review: structure, properties and nanocomposites. Chem. Soc. Rev. 2011, 40, 3941-3994. (27) Habibi, Y.; Lucia, L. A.; Rojas, O. J. Cellulose Nanocrystals: Chemistry, Self-Assembly, and Applications. Chem. Rev. 2010, 110, 3479-3500. (28) Ramage, M. H.; Burridge, H.; Busse-Wicher, M.; Fereday, G.; Reynolds, T.; Shah, D. U.; Wu, G. L.; Yu, L.; Fleming, P.; Densley-Tingley, D.; Allwood, J.; Dupree, P.; Linden, P. F.; Scherman, O. The wood from the trees: The use of timber in construction. Renew. Sust. Energ. Rev. 2017, 68, 333-359. (29) Li, Y. Y.; Fu, Q. L.; Yu, S.; Yan, M.; Berglund, L. Optically Transparent Wood from a Nanoporous Cellulosic Template: Combining Functional and Structural Performance. Biomacromolecules 2016, 17, 1358-1364. (30) Gierlinger, N.; Goswami, L.; Schmidt, M.; Burgert, I.; Coutand, C.; Rogge, T.; Schwanninger, M. In situ FT-IR microscopic study on enzymatic treatment of poplar wood cross-sections. Biomacromolecules 2008, 9, 2194-2201.


Page 30 of 33

Page 31 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(31) Janpetch, N.; Vanichvattanadecha, C.; Rujiravanit, R. Photocatalytic disinfection of water by bacterial cellulose/N-F co-doped TiO2 under fluorescent light. Cellulose 2015, 22, 33213335. (32) Pandey, K. K.; Pitman, A. J. FTIR studies of the changes in wood chemistry following decay by brown-rot and white-rot fungi. Int. Biodeterior. Biodegrad. 2003, 52, 151-160. (33) Ji, Z.; Ma, J. F.; Zhang, Z. H.; Xu, F.; Sun, R. C. Distribution of lignin and cellulose in compression wood tracheids of Pinus yunnanensis determined by fluorescence microscopy and confocal Raman microscopy. Ind. Crop. Prod. 2013, 47, 212-217. (34) Zhang, Q. F.; Myers, D.; Lan, J. L.; Jenekhe, S. A.; Cao, G. Z. Applications of light scattering in dye-sensitized solar cells. Phys. Chem. Chem. Phys. 2012, 14, 14982-14998. (35) Jiang, F.; Li, T.; Li, Y. J.; Zhang, Y.; Gong, A.; Dai, J. Q.; Hitz, E.; Luo, W.; Hu, L. B. Wood-Based Nanotechnologies toward Sustainability. Adv. Mater. 2018, 30, 1703453. (36) Merindol, R.; Diabang, S.; Felix, O.; Roland, T.; Gauthier, C.; Decher, G. Bio-inspired multiproperty materials: strong, self-healing, and transparent artificial wood nanostructures. ACS Nano 2015, 9, 1127-1136. (37) Schrage, C.; Kaskel, S. Flexible and Transparent SWCNT Electrodes for Alternating Current Electroluminescence Devices. ACS Appl. Mater. Interfaces 2009, 1, 1640-1644. (38) MacDonald, W. A. Engineered films for display technologies. J. Mater. Chem. 2004, 14, 4-10. (39) Yu, J.; Paterson, N.; Blamey, J.; Millan, M. Cellulose, xylan and lignin interactions during pyrolysis of lignocellulosic biomass. Fuel 2017, 191, 140-149. (40) Xiong, W. W.; Liu, H. L.; Chen, Y. Z.; Zheng, M. L.; Zhao, Y. Y.; Kong, X. B.; Wang,



Y.; Zhang, X. Q.; Kong, X. Y.; Wang, P. F.; Jiang, L. Highly Conductive, Air-Stable Silver Nanowire@Iongel Composite Films toward Flexible Transparent Electrodes. Adv. Mater. 2016, 28, 7167-7172. (41) Brett, C. J.; Mittal, N.; Ohm, W.; Gensch, M.; Kreuzer, L. P.; Körstgens, V.; Månsson, M.; Frielinghaus, H.; Müller-Buschbaum, P.; Söderberg, L. D.; Roth, S. V. Water-Induced Structural Rearrangements on the Nanoscale in Ultrathin Nanocellulose Films. Macromolecules 2019, 52, 4721-4728. (42) Chen, W. M.; Xu, Y. C.; Shi, S. K.; Thiphuong, N.; Chen, M. Z.; Zhou, X. Y. Fast enhancement on bondability of wheat straw surface for bio-composites manufacture via dielectric barrier discharge plasma. RSC Adv. 2016, 6, 108566-108572. (43) Kondyurin, A.; Lauke, B. Curing of liquid epoxy resin in plasma discharge. Eur. Polym. J. 2004, 40, 1915-1923. (44) Wang, J. X.; Yan, C. Y.; Chee, K. J.; Lee, P. S. Highly Stretchable and Self-Deformable Alternating Current Electroluminescent Devices. Adv. Mater. 2015, 27, 2876-2882. (45) Ma, S. W.; Peng, Z. L.; Kitai, A. H. A CuO Nanowire-Based Alternating Current Oxide Powder Electroluminescent Device with High Stability. Angew. Chem.-Int. Edit. 2018, 57, 11267-11272. (46) Huang, J.; Yang, Y.; Xue, S. H.; Yang, B.; Liu, S, Y.; Shen, J. Photoluminescence and electroluminescence of ZnS:Cu nanocrystals in polymeric networks. Appl. Phys. Lett. 1997, 70, 2335-2337. (47) Yan, C. Y.; Wang, J. X.; Kang, W. B.; Cui, M. Q.; Wang, X.; Foo, C. Y.; Chee, K. J.; Lee, P. S. Highly Stretchable Piezoresistive Graphene-Nanocellulose Nanopaper for Strain


Page 32 of 33

Page 33 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Sensors. Adv. Mater. 2014, 26, 2022-2027.

Table of Contents


Constructing novel electroluminescent device with high

Recommend Documents